Use of amphiphiles for permanent improvement of colorant compatibility of polyolefin-based shaped bodies, fibers and films

ABSTRACT

A polyolefin composition having enhanced dyeing capabilities containing: (a) a polyolefin; (b) from 0.01 to 10% by weight, based on the weight of the polyolefin in, of a migratable amphiphile, excluding phenolic and sulfur-containing stabilizers and n-octyl phenyl salicylate; and (c) from 0.01 to 1000 ppm of a transition metal, based on the weight of the polyolefin.

BACKGROUND OF THE INVENTION

This invention relates to the use of amphiphiles for permanentlyimproving the dye compatibility of polyolefin-based moldings, fibers andfilms.

In many cases, the surface of plastic products has to be provided withthree-dimensional, color or other effects which either can only beproduced in completely, if at all, during the forming process fortechnical reasons or can only be inelegantly produced for economicreasons.

This applies, for example, to the dyeing and printing of the surfaces ofpolyolefin-based moldings, fibers and films. On account of theirnon-polar character, high molecular weight hydrocarbons, such aspolyethylene or polypropylene, have a low surface tension (typically ofthe order of 20 to 30×10⁻⁵ Ncm⁻¹. The adhesion of printing inks and dyesto their surface is correspondingly weak (typically below 0.5 Nmm⁻²).

It is known from the prior art that the compatibility of plasticsurfaces with can be improved, for example, by oxidative aftertreatmentprocesses, such as corona or plasma treatment. In processes such asthese, the surface of the plastic is oxidized or chemically modified inthe presence of gases and discharges, so that certain surface propertiesof the plastic can be modified. However, apart from their high energyconsumption, processes such as these always involve an additional stepand lead to ozone emissions in the manufacture of plastic parts.

Chemical pretreatment processes, including for example treatment withfluorine or chlorine gas, with chromosulfuric acid or fluorosulfonicacid, etc., have also been known for some time.

In addition, special substances which were applied to the surface of theplastic to make the problematical dyeability of polyolefins morefavorable were known from the earlier literature.

Thus, even U.S. Pat. No. 3,284,428 points out the dyes adhere verypoorly to polyolefin fibers because the polyolefins have an inertsurface. It is also pointed out that although polypropylene, forexample, can be dyed, the dye absorption rate is far too low forindustrial technical requirements. U.S. Pat. No. 3,284,428 proposes theuse of nickel derivatives of special diamines to solve this problem.

U.S. Pat. No. 3,424,716 describes polyolefins to which ternary mixturesof nickel compounds, sulfo compounds and n-octylphenyl salicylate areadded as additives in order to improve the dyeability and stability ofthe polyolefins.

EP-B-372 890 describes polyolefin- or polyester-based fibers with alubricant applied to their surface. This lubricant comprises a mixtureof (1) fatty acid diethanolamide, (2) a polyether-modified silicone, (3)a sorbitan fatty acid ester and (4) a metal salt of an alkyl sulfonate.Components (1) to (4) are present in special quantity ratios. Accordingto page 3, lines 20 to 26, the mixture of components (1) to (4) isapplied to the surface. The technique by which the mixture containingthe four components is applied to the surface of fibers is described indetail on page 4, lines 6 to 9. The application techniques mentionedinclude a) the use of rollers, b) spraying and c) immersion.Accordingly, the process according to EP-B-372 890 is a process in whicha mixture of components (1) to (4) is applied to the surface ofpolyolefin moldings in an additional processing step. Accordingly, theexpression “applied to the fiber surface” used in claim 1 of EP-B-372890 may be clearly interpreted by the expert to mean that any adhesioninvolved is loose and temporary, for example in the form of relativelyweak adhesion forces, and cannot in any way to be considered torepresent permanent anchorage.

Even the more recent literature (both patent documents and scientificpublications) that the dyeability of polyolefins is extremelyproblematical. For example, EP-B-595 408 describes a process forimproving the surface compatibility properties of polypropylene whichcomprises heat-treating polypropylene together with at least one olefincompound polybrominated at an aromatic ring in the absence of freeradical initiators.

U.S. Pat. No. 5,045,387 describes the treatment of polyolefin-basedfibers or films in which special polyalkoxylated polydimethyl siloxanesor alkoxylated ricinoleic acid derivatives are applied to the surface.

In a fairly recent Article, J. Akrman and J. Prikryl investigate thedyeing behavior of polypropylene fibers (cf. Journal of Applied PolymerScience 1996, Vol. 62, pages 235-245). The authors of this Article pointout that the causes behind the poor dyeability of polypropylene havebeen known for some time and lie in the fact that the material has highcrystallinity and an extremely non-polar aliphatic structure which doesnot contain any reactive sites. The authors also point out that althoughadditives containing basic nitrogen are known from the prior art, noseriously commercial product which satisfactorily solves the dyeabilityproblems is available to the expert despite the intensive researchefforts in this field. The authors then report—on the basis of their ownstudies—that a polypropylene fiber dyeable in acidic medium can beobtained by adding a special high molecular weight additive containingbasic nitrogen on a rigid polymer chain to the polymer before it isextruded.

In view of the very widely used traditional chemical aftertreatmentprocesses, such as corona and plasma treatment, it is known to theexpert that no exact statements can be made as to the various processesinvolved. However, it has been established that oxidative surfacechanges occur and result in the formation of certain “active centers”.However, their concentration generally decreases with time so that thepretreatment effect also is only in evidence for a certain time,generally not more than 72 hours (cf. for example, Klaus Stoeckert(Editor), “Veredein von Kunststoff-Oberflächen”, Munich 1974, page 137).

One feature common to all the known processes is that, in general, thedesired surface effects are only temporarily present.

EP-B-616 622 relates to extrudable compostable polymer compositionscomprising an extrudable thermoplastic polymer, copolymer or mixturesthereof containing a degradation-promoting system of an auto-oxidativecomponent and a transition metal. The auto-oxidative system comprises afatty acid, a substituted fatty acid or derivatives or mixtures thereof,the fatty acid having 10 to 22 carbon atoms and containing at least 0.1%by weight of unsaturated compounds and at least 0.1% by weight of freeacid. The transition metal is present in the composition in the form ofa salt in a quantity of 5 to 500 ppm and is selected from the groupconsisting of cobalt, manganese, copper, cerium, vanadium and iron. Thecomposition is said to be oxidatively degradable to a brittle materialin the form of a film around 100 microns thick over a period of 14 daysat 60° C. and at a relative air humidity of at least 80%.

DESCRIPTION OF THE INVENTION

The problem addressed by the present invention was to provideauxiliaries with which the dye compatibility of polyolefin-basedmoldings, fibers and films could be lastingly and permanently improved.

There are no restrictions to the expression “dyes” as used in thecontext of the present invention. In principle, therefore, any naturaland/or synthetic dyes familiar to the expert and, more particularly, thedyes traditionally used in the dyeing of textiles may be used for thepurposes of the present invention. Of particular importance in thisregard are the synthetic dyes which are normally divided into thefollowing groups: basic dyes (also known as cationic dyes), mordantdyes, direct dyes (also known as substantive dyes), dispersion dyes,development dyes, oxidation dyes, color lakes, vat dyes, leuco vat dyeesters, metal complex dyes, pigments, reactive dyes and acid dyes (cf.for example, Ullmanns Encyclopädie der technischen Chemie, 4th Edition,Vol. 11, Chapter entitled “Farbstoffe, synthetische”, more particularlypages 138-139). All these dyes are specifically included in the scope ofthe present invention. Printing inks are also specifically regarded asdyes in the context of the present invention.

The present invention relates to the use of amphiphiles for permanentlyimproving the dye compatibility of polyolefin-based moldings, fibers andfilms, characterized in that a mixture containing

a) predominantly one or more polyolefins,

b) 0.01 to 10% by weight, based on the polyolefins, of one or moremigratable amphiphiles (additives I) and

c) 0.01 to 1000 ppm of one or more transition metal compounds (II)—metalcontent of the transition metal compounds (II) based on the polyolefins—

is subjected in the usual way to molding by extrusion, calendering,injection molding and the like at temperatures in the range from 180 to320° C.

The additives according to the invention are also referred tohereinafter as additives (I). They are amphiphilic compounds. Anamphiphile is understood in common usage to be a compound which combineshydrophilic and hydrophobic molecule parts. In other words, themolecular structure of amphiphiles contains as it were a “combination”of a suitable oleophilic basic molecule based on a hydrocarbon whichcontains one or more substituents of high polarity. The substituents ofhigh polarity are formed in known manner by hetero atom-containingmolecule constituents, particular significance being attributed in thisregard to the hetero atoms oxygen, nitrogen and/or halogen for formingthe functional group(s) of high polarity.

The use of the amphiphiles in accordance with the invention ensures thatdyes are able permanently to adhere to or in the plastic without anyadditional pretreatment. Dye compatibility values once establishedremain intact for long periods or occasionally even increase in theevent of continuing storage. It is specifically pointed out that,basically, the dyes adhere directly to or in the plastic, but notbecause they are present for example in an applied layer of paint or thelike.

By adhesion “to or in the plastic” is meant that, although on the onehand the dyes adhere in the region of the plastic surface to which themigratable amphiphilic additives at least partly pass in the course ofthe molding process, on the other hand dyes can also diffuse into theinterior of the plastic where they come into contact—in the sense ofadhesion—with the additives present there.

The mixture containing components a), b) and c) is used by traditionalmolding techniques well-known to the expert, such as extrusion,calendering, injection molding and the like. In a preferred embodimentof the present invention, the melt of the mixture containing componentsa), b) and c) comes into contact with oxygen, more especiallyatmospheric oxygen, in the course of the molding process. In the case ofextrusion, for example, this happens when the melt leaves the extruderthrough the extrusion die. The preferred embodiment mentioned aboveenables—optionally catalytically assisted—oxidative processes, forexample oxidatively induced crosslinking—and hence ultimatelyimmobilization—of olefinically unsaturated molecule constituents of theadditives (I) to form relatively high molecular weight compounds,oxidatively induced oxidation of activated methylene groups which arepresent in the immediate neighborhood of the polar groups of theamphiphiles (I) and other oxidative reactions and secondary reactions totake place. (Atmospheric) oxygen can act on the one hand on the surfaceitself and, on the other hand, even in the interior of the plastic,especially in zones near the surface—to which it is capable ofdiffusing.

The additives (I) suitable for use in accordance with the presentinvention have relatively low molecular weights, a pre-requisite forreasonably rapid migration. An upper limit to the molecular weight ofsuitable internal additives (I) is at about 5,000 D (dalton), preferablyat values of at most about 3,000 D and more preferably at maximum valuesof about 1,000 D. The expression of molecular weight in “daltons” isknown to be the definition of the absolute molecular weight.Accordingly, by comparison with the polyolefins with their molecularweights of several million, the additives (I) are comparatively lowmolecular weight compounds. The lower limit to the molecular weight ofthese internal additives (I) is at about 50 to 100 D, preferably at 150to 180 D and more preferably at around 200 to 300 D.

The use of the amphiphiles in accordance with the invention guaranteesthe compatibility of dyes subsequently applied with the polyolefinsurface with virtually no time limit. The expression “with virtually notime limit” applies both to the time interval between production of theparticular polyolefin-based molding and its surface dyeing in a separateprocess step and to the time interval between production of the dyedproduct and its practical application.

The preferred additives (I) according to the invention are amphiphilesof which the hydrophobic molecule parts at least partly containolefinically unsaturated functions which are particularly readilyaccessible to radical-induced crosslinking reactions in the vicinity ofthe plastic surface. Preferred additives (I) are those which, in theunreacted state, have iodine values of at least about 10, preferably ofat least about 30 to 40 and more preferably of at least about 45 to 50.The choice of the method by which the iodine value is determined isbasically of minor importance. In the context of the present invention,however, reference is specifically made to the methods developed byHanus and Wijs, which have long been part of Section C-V of the“DGF-Einheitsmethoden”, and to the equivalent method developed by Fiebig(cf. Fat Sci. Technol. 1991, No. 1, pages 13-19).

As will be shown in more detail hereinafter, both monoolefinicallyunsaturated hydrocarbon radicals and polyolefinically unsaturatedhydrocarbon radicals may be provided in the additives (I) used inaccordance with the invention. Combinations of several correspondingcompounds are also important auxiliaries for the use according to theinvention. The iodine values of the additives (I) used may assume valuesabove 80 to 90 and, more particularly, values above 100. Highlyunsaturated additive components with iodine values of up to about 200 oreven higher, for example in the range from 120 to 170, are auxiliariesin the context of the use according to the invention.

In the three-dimensional structure of their hydrocarbon radical, theseinternal additives (I) may be both straight-chained and branched and/ormay have a cyclic structure.

Basically, suitable substituents of high polarity are functional groupswhich are distinguished in particular by a content of hetero atoms andpreferably by a content of O, N and/or halogen. The expression“functional group” is used in its most general sense in the context ofthe present invention and is understood to apply to groups of atomswhich have a characteristic reactivity and which contain one or morehetero atoms. Accordingly, this definition encompasses for example OHgroups (simple atomic groups) or N-containing heterocycles (more complexatomic groups), but not C═C-double bonds (no hetero atom) per se, unlessthey are present in addition to the hetero atoms in more complex atomicgroups. Groups from the following classes are mentioned purely by way ofexample: carboxyl, hydroxyl, amino, oxazoline, imidazoline, epoxideand/or isocyanate groups and/or derivatives thereof. The group of suchderivatives includes, for example, ester groups, ether groups, amidegroups/alkanolamine and/or alkanolamide groups.

A very important class of substituents of high polarity in the contextof the present invention are N-containing heterocycles and/orderivatives thereof, for example pyridazine, pyrimidine, pyrazine,pyridine, azane and azinane groups. Thiazole, thiazolane, thiazolidine,pyrrole, azolane, azolidine, pyrazole and isooxazole groups areparticularly suitable, imidazole, imidazoline, diazolidine, oxazoline,oxazole, oxazolidine and oxazolidane groups being most particularlysuitable.

A particularly preferred class of additives (I) are compounds which, onthe one hand, contain one or more olefinically unsaturated functions inthe hydrophobic part of the molecule and, on the other hand, extremelypolar functions, such as oxazoline, imidazoline, sulfonate, phosphonateor carboxyl groups (or salts thereof), in the hydrophilic part of themolecule.

Certain individually selected additives of the type mentioned in theforegoing and mixtures of several corresponding auxiliaries may be usedas the additive (I). By suitably selecting the substituents of highpolarity in the particular auxiliaries of this class of additives used,the dye compatibility to which the end product is to be adjusted can beinfluenced in a predetermined manner. However, mixtures of the type inquestion here are also corresponding mixtures which, so far as theirfunctional group is concerned, can be assigned to a sub-class, i.e. forexample contain carboxyl groups as substituents of high polarity, butcontain different basic structures in their hydrocarbon molecule. It isknown that corresponding mixtures are obtained in particular whenmixtures of the type in question based on natural materials are used.For example, olefinically unsaturated fatty acid mixtures of vegetableand/or animal origin or derivatives thereof can form valuable additivesof the additive (I) type in the context of the teaching according to theinvention.

As known per se to the expert, different improvements in dyecompatibility can be expected according to the particular groups of highpolarity present. Relevant specialist knowledge may be applied in thisregard.

Another possibility of varying the internal additives (I) according tothe invention lies in the number of functional substituents of highpolarity in the particular basic hydrocarbon skeleton. Even onesubstituent of high polarity can lead to the permanent and at the sametime marked increase in dye compatibility required, especially afteradaptation of the type and quantity of functional groups available. Inaddition, however, it has been found that the presence of two or moresuch substituents of high polarity in the particular molecule of theadditive (I) can be an important additional feature for increasing dyecompatibility. Reference is made here purely by way of example to theclass of so-called dimer fatty acids. Dimer fatty acids are known amongexperts to be carboxylic acids obtainable by oligomerization ofunsaturated carboxylic acids, generally fatty acids, such as oleic acid,linoleic acid, erucic acid and the like. The oligomerization is normallycarried out at elevated temperature in the presence of a catalyst, forexample of alumina. The products obtained are mixtures of varioussubtonics in which the dimerization products predominate. However, smallamounts of higher oligomers, especially trimer fatty acids, are alsopresent. Dimer fatty acids also contain monomers or monofunctional fattyacids from their production. Dimer fatty acids are commerciallyavailable products and are marketed in various compositions andqualities. In the same way as dimer fatty acids, trimer fatty acids areoligomerization products of unsaturated fatty acids in which thepercentage content of trimers in the product predominates. Dimer andtrimer fatty acids have olefinic double bonds which make them capable ofreactive solidification in the vicinity of the polyolefin surface.

Dialkanolamines containing at least partly olefinically unsaturatedhydrocarbon radicals or dialkanolamides of unsaturated fatty acids areextremely effective dye compatibility improvers in the context of theteaching according to the present invention. This applies in particularto the corresponding diethanol derivatives. This class includes, forexample, oleic acid diethanolamide and linoleic acid diethanolamide.Specifically included in this connection are technical products known tothe expert, including the secondary components normally occurringtherein. Examples of such products are “Comperlan OD” (technical oleicacid diethanolamide) and “Comperlan F” (technical linoleic aciddiethanolamide), both commercial products of Henkel KGaA. However, suchcompounds as sorbitan monoesters with, in particular, ethylenicallyunsaturated fatty acids also lead to optimal results in the context ofthe teaching according to the invention.

The migration rate to be expected from the molecular structure of theparticular additives (I) used may be one of the factors which determinesthe quantity of additives (I) to be used in each individual case. Lowerlimits to the size of the additions of additive (I) to the polyolefinare about 0.01% by weight and, more particularly, about 0.1% by weight.In general, it will be advisable to use at least about 0.2 to 0.8% byweight (based on the polyolefins). Optimum dye compatibility values forthe particular representatives of this class of substances used in eachindividual case as the additive (I) are generally achieved in the rangefrom about 0.3 to 5% by weight and, more particularly, in the range from0.4 to about 1% by weight.

As already mentioned, the optimum dye compatibility to be adjusted isunderstandably determined by the chemical nature and by the possibleinteraction of the substituents of high polarity and optionallyreactivity in the additive (I). The choice of additive (I) to be used ineach individual case is determined by the particular stresses likely tobe applied in the end product to the strength of the bond between thepolyolefin and the dye applied.

The combination of the teaching according to the invention which leadsto high dye compatibility values with technologies known per se forimproving dye compatibility on polyolefin surfaces falls within thescope of the teaching according to the invention. Thus, both mechanicaland chemical and/or physical surface treatments of the outer polyolefinsurface may be combined with the dye compatibility modificationsaccording to the invention. However, this is generally not necessary.

As already mentioned, the additives (I) are used in combination withtransition metal compounds (II) during the molding of the polyolefins.The quantity of transition metal compound (II)—metal content of thetransition metal compound (II) based on the polyolefins—is in the rangefrom 0.1 to 1000 ppm. Basically, there are no particular restrictions inregard to the nature of the transition metal compounds (II). Inprinciple, therefore, any transition metal compounds known to the expertmay be used for the purposes of the teaching according to the invention.In one embodiment, transition metal salts, preferably salts based onorganic acids containing 8 to 22 carbon atoms, are used as thetransition metal compounds (II). In another embodiment, the transitionmetals are selected from the group consisting of lead, nickel,zirconium, chromium, titanium and tin. In another embodiment, thetransition metal compounds are used in a quantity of less than 5ppm—metal content of the transition metal compound (II) based on thepolyolefins. Instead of or in addition to the metals just mentioned,cobalt, copper, iron, vanadium, cerium and magnesium, for example, mayalso be used.

If desired, other compounds known to the expert as catalysts foroxidative processes may be used in addition to the compulsory transitionmetal compounds (II) mentioned.

In one preferred embodiment, the ratio by weight of the additives (I) tothe metal content of transition metal compounds (II) is adjusted to avalue of 10:0.1 to 10:10⁻⁷, preferably to a value of 10:0.02 to 10:10⁻⁶and more preferably to a value of 10:0.01 to 10:10⁻⁵.

In the light of the teaching of EP-B-616 622 cited earlier on, thefollowing observations may be made:

The teaching of the present invention on the one hand ensures that theimproved and permanent dye compatibility required is achieved and, onthe other hand, that it is achieved without any adverse effect on othermaterial parameters.

In one preferred embodiment, the transition metal compounds (II) areused in combination with additives (I) selected from the class ofdiethanolamides of unsaturated fatty acids. As already mentioned, thediethanolamides are preferably used as technical products.

According to the invention, the amphiphilic additives (I) are used inthe course of routine molding processes, such as extrusion, calendering,injection molding and the like. It may be desirable to use componentsa), b) and c) in the form of a mixture prepared in advance. Othertypical auxiliaries which have generally been successful in the moldingof plastics and which are known to the expert, for example slip agents,antistatic agents, lubricants, release agents, UV stabilizers,antioxidants, fillers, fire retardants, mold release agents, nucleatingagents and antiblocking agents, may also be separately made up and addedduring the final mixing of the end products. However, it may also bedesirable, for example where extrusion is applied, to introducecomponents b) and/or c) and/or other additives either completely orpartly into the polyolefin melt itself in the extruder, so that themixture of components a), b) and c)—and optionally other auxiliaries—isnot present from the outset as a made-up product, but is formed in theextruder itself. A technique such as this is appropriate, for example,when the additives (I) to be added to the polymer melt are present inliquid form and are easier to inject than to make up in advance.

It may even be desirable, although not necessary for obtaining theeffect according to the invention, to undertake a conventional corona orplasma treatment after the use of components a) to c) in accordance withthe invention.

Basically, any known ethylene- or propylene-based polymers andcopolymers may be used as the basic oleophilic polyolefin material.

Mixtures of pure polyolefins with copolymers are also suitable inprinciple providing the additives (I) retain their ability to migrate inaccordance with the invention and hence to collect at the surfaces ofsolids. Polymers particularly suitable for the purposes of the teachingaccording to the invention are listed below: poly(ethylenes), such asHDPE (high-density polyethylene), LDPE (low-density polyethylene), VLDPE(very-low-density polyethylene), LLDPE (linear low-densitypolyethylene), MDPE (medium-density polyethylene), UHMPE (ultrahighmolecular polyethylene), VPE (crosslinked polyethylene), HPPE(high-pressure polyethylene); isotactic polypropylene; syndiotacticpolypropylene; Metallocen-catalyzed polypropylene, high-impactpolypropylene, random copolymers based on ethylene and propylene, blockcopolymers based on ethylene and propylene; EPM(poly[ethylene-co-propylene]); EPDM(poly[ethylene-co-propylene-co-conjugated diene]).

Other suitable polymers are: poly(styrene); poly(methylstyrene);poly(oxymethylene); Metallocen-catalyzed α-olefin or cycloolefincopolymers, such as norbornene/ethylene copolymers; perfluorinatedpolyolefins, polyvinyl chloride, acrylonitrile/butadiene/styrenecopolymers (ABS), styrene/butadiene/styrene or styrene/isoprene/styrenecopolymers (SIS or SBS); copolymers containing at least 80% ethyleneand/or styrene and less than 20% monomers, such as vinyl acetate,acrylates, methacrylates, acrylic acid, acrylonitrile, vinyl chloride.Examples of such polymers are: poly(ethylene-co-ethyl acrylate),poly(ethylene-co-vinyl acetate), poly(ethylene-co-vinyl chloride),poly(styrene-co-acrylonitrile). Also suitable are graft copolymers andpolymer blends, i.e. mixtures of polymers in which the above-mentionedpolymers inter alia are present, for example polymer blends based onpolyethylene and polypropylene.

Homopolymers and copolymers based on ethylene and propylene areparticularly preferred for the purposes of the present invention. In oneembodiment of the present invention, therefore, polyethylene on its ownis used as the polyolefin; in another embodiment, polypropylene on itsown is used as the polyolefin and, in a further embodiment,ethylene/propylene copolymers are used as the polyolefin.

The surface-modified polyolefin-based moldings and films obtained by theprocess according to the invention can be printed and dyed by any of therelevant methods known to the expert. Traditional acidic, basic orreactive wool or cotton dyes are preferably used for dyeing.

The present invention also relates to a process for the production ofdyed and/or printed polyolefin-based moldings, fibers and films,characterized in that a mixture containing

a) predominantly one or more polyolefins,

b) 0.01 to 10% by weight, based on the polyolefins, of one or moremigratable amphiphiles (additives I) and

c) 0.01 to 1000 ppm of one or more transition metal compounds (II)—metalcontent of the transition metal compounds (II) based on the polyolefins,

is conventionally molded by extrusion, calendering, injection moldingand the like at temperatures of 180 to 320° C. and the resultingpolyolefin-based moldings, fibers and films with improved dyecompatibility are then printed and/or dyed by conventional methods.

The following Examples are intended to illustrate the invention withoutlimiting it in any way.

EXAMPLE

1. Materials Used

1.1. Polyolefin

In all the tests, a granular polypropylene (“Hostalen PPH 2150”, aproduct of Hoechst AG) was used as the high molecular weight polyolefin.

1.2. Additives (I)

Soya oxazoline: oxazoline of soya fatty acids (technical quality)(“Loxamid VEP 8514”, a product of Henkel KGaA, Düsseldorf)

Ricinol oxazoline: oxazoline of castor oil fatty acid (technicalquality) (“Loxamid VEP 8513”, a product of Henkel KGaA, Düsseldorf)

Comperlan F: linoleic acid diethanolamide, technical quality (“ComperlanF”, a product of Henkel KGaA, Düsseldorf)

Edenor HTiCT: selectively hydrogenated tallow fatty acid (“EdenorHTiCT”, a product of Henkel KGaA, Düsseldorf)

1.3. Transition Metal Compounds (II)

Pb-C8: lead-2-ethylhexanoate (lead salt of 2-ethylhexanoic acid)

Ni-acac: nickel acetyl acetonate

Cu-sol: mixture containing 62% copper(II) salts of branched C₆₋₁₉ fattyacids and Cu(II) naphthenate and 9% C₃₋₂₄ fatty acids and 35% by weightnaphtha (“Cu-Soligen”, a product of Borchers GmbH)

1.4. Other Substances

Dye 1 commercial acid dye (“Supracen Rot 3B 200%”, a product of BayerAG)

Dye 2 commercial reactive dye (“Levafix Brillantrot E-4BA”, a product ofBayer AG

Dye 3 commercial basic dye (“Astrazonrot 6B”, a product of Bayer AG)

2. Production of Surface-modified Polypropylene by the Process Accordingto the Invention

In order to test the dye compatibility properties of surface-modifiedpolypropylene, polypropylene was initially produced in tape form bymixing 600 g of polypropylene granules with 9.0 g (=1.5%) of additive(I) and 0.38 g of transition metal compound (II). The particularadditive (I) and transition metal compound (II) used are shown in Tables1 to 3 below. The mixtures were introduced through a hopper into anextruder. A Brabender DSK 42/7 twin-screw extruder (Brabender OHG,Duisberg) was used.

As well-known to the expert, an extruder is a machine for processingplastics in which both powder-form and granular thermoplastics can becontinuously mixed and plasticized.

Beneath the feed hopper, there is a contra-rotating twin screwlongitudinally divided into three heating zones in addition to awater-cooling system which is intended to prevent premature melting ofthe granules or powder. The temperature of the heating zones and therotational speed of the twin screws can be controlled through adata-processing Plast-Corder PL 2000 which is connected to the extrudervia a PC interface.

To produce the polypropylene tapes, the following temperatures wereadjusted: heating zone I 250° C., heating zone II 270° C., heating zoneIII 290° C., the three heating zones being air-cooled to keep thetemperatures constant.

The polypropylene granules (including the particular additive I and thetransition metal compound II) were automatically taken into the extruderby the contra-rotating twin screws and transported along the screw. Therotational speed was 25 r.p.m. This guaranteed a relatively longresidence time in the extruder and hence thorough compounding andhomogenization. The resulting homogeneous and substantially bubble-freemixture finally entered a nozzle which represents a fourth heating zone.The temperature of the nozzle was 300° C., i.e. the particular mixtureleft the extruder at that temperature.

After leaving the nozzle, the hot mixture flowed onto a conveyor belt ofwhich the speed was adjusted so that a smooth and uniformly thick andwide tape was formed on cooling in air. In the tests described here, thespeed was adjusted so that the polypropylene tape was about 35 mm wideand about 0.35 mm thick. Square test specimens were die-cut from thismaterial and used for the dyeing tests described hereinafter.

Test specimens of pure polypropylene were used for comparison purposes.They were produced by the extrusion technique just described, exceptthat polypropylene granules on their own, i.e. with no additive I ortransition metal compound II added, were used. The test results based onthis material are identified in Tables 1 to 3 by the abbreviation“Comp.” In the first column.

3. Dyeing Tests with Acid Dye

3.1. Preparation of the Dyeing Solution A

Beginning at 50° C., Supracen Rot (dye “Dye 1”) was added to 1 liter ofwater in such a quantity that the concentration of the dye was 1.5%. 1.5g of sodium sulfate calc. was then added, a pH value of 2 to 3.5 wasadjusted with 85% formic acid and the whole was heated to boilingtemperature at a rate of about 2° C. per minute. The dyeing solutionthus prepared was used to test the dye compatibility of polypropylenetest specimens.

3.2. Dyeing and Evaluation

Untreated polypropylene test specimens and polypropylene test specimenssurface-modified in accordance with the invention were first stored for1 to 7 days at 20 to 60° C. and then immersed for 60 minutes in thedyeing solution prepared in accordance with 3.1, the boiling temperaturebeing maintained. The test specimens were then removed from the bath andrinsed with water first for 5 minutes at 50° C. and then for another 5minutes at 20° C. The dyeing results were visually evaluated by a panelof examiners using a “school marking system”. The individual values(“marks”) have the following meanings: 1=very good, 2=good,3=satisfactory, 4=adequate, 5=poor, 6=inadequate. The value “1”corresponds to the mark awarded in the corresponding dyeing of cottonwhile the value “6” corresponds to the mark awarded in the dyeing ofuntreated polypropylene.

The test results are set out in Table 1 below. All the results areaverage values from five tests.

TABLE 1 Dyeing tests with acid dye (dyeing solution A) Transition metalcompound Storage Result No. Additive (I) II Days ° C. Dye (mark) Comp.None None 1 20 Dye 1 6 Comp. None None 6 20 Dye 1 6 Comp. None None 1 60Dye 1 6 Comp. None None 6 60 Dye 1 6 B1 Soya oxazoline Pb-C8 2 20 Dye 11 B2 Soya oxazoline Pb-C8 7 60 Dye 1 1 B3 Soya oxazoline Niacac 3 20 Dye1 1 B4 Soya oxazoline Niacac 7 60 Dye 1 1 B5 Soya oxazoline Cu-sol 2 20Dye 1 1 B5 Soya oxazoline Cu-sol 7 60 Dye 1 1 B6 Ricinol oxazoline Pb-C82 20 Dye 1 2 B7 Ricinol oxazoline Pb-C8 7 60 Dye 1 2 B8 Ricinoloxazoline Niacac 3 20 Dye 1 2 B9 Ricinol oxazoline Niacac 7 60 Dye 1 2B10 Ricinol oxazoline Cu-sol 2 20 Dye 1 2 B11 Ricinol oxazoline Cu-sol 760 Dye 1 1 B12 Comperlan F Cu-sol 1 20 Dye 1 3 B13 Comperlan F Cu-sol 660 Dye 1 2 B14 Comperlan F Pb-C8 6 60 Dye 1 3 B15 Comperlan F Niacac 660 Dye 1 3 B16 Edenor HTiCT Cu-sol 1 20 Dye 1 3 B17 Edenor HTiCT Cu-Sol6 60 Dye 1 4 B18 Edenor HTiCT Pb-C8 1 20 Dye 1 3 B19 Edenor HTiCT Pb-C86 60 Dye 1 4

4. Dyeing Tests with Reactive Rye

4.1. Preparation of the Dyeing Solution B

Beginning at 25° C., 50 g of sodium sulfate calc. were added to 1 literof water. After 5 minutes, 5 g of sodium bicarbonate were added, afteranother 5 minutes 5 g of soda were added and, after another 5 minutes,Levafix Brillantrot E-4BA (dye “Dye 2”) was added in such a quantitythat the concentration of the dye was 1.5%. The solution was then heatedto 60° C. at a rate of about 2° C. per minute. The dyeing solution thusprepared was used to test the dye compatibility of polypropylene testspecimens.

4.2. Dyeing and Evaluation

Untreated polypropylene test specimens and polypropylene test specimenssurface-modified in accordance with the invention were first stored for1 to 8 days at 20 to 60° C. and then immersed for 45 minutes in thedyeing solution prepared in accordance with 4.1, the boiling temperaturebeing maintained. The test specimens were then removed from the bath andrinsed with water first for 5 minutes at 50° C. and then for another 5minutes at 20° C. The dyeing results were visually evaluated by a panelof examiners using a “school marking system”. The individual values(“marks”) have the following meanings: 1=very good, 2=good,3=satisfactory, 4=adequate, 5=poor, 6=inadequate. The value “1”corresponds to the mark awarded in the corresponding dyeing of cottonwhile the value “6” corresponds to the mark awarded in the dyeing ofuntreated polypropylene.

The test results are set out in Table 2 below. All the results areaverage values from five tests.

TABLE 2 Dyeing tests with reactive dye (dyeing solution B) Transitionmetal compound Storage Result No. Additive (I) II Days ° C. Dye (mark)Comp. None None 1 20 Dye 2 6 Comp. None None 6 20 Dye 2 6 Comp. NoneNone 1 60 Dye 2 6 Comp. None None 6 60 Dye 2 6 B20 Soya oxazoline Pb-C88 60 Dye 2 2 B21 Soya oxazoline Niacac 8 60 Dye 2 3 B22 Soya oxazolineCu-sol 8 60 Dye 2 2 B24 Ricinol oxazoline Pb-C8 8 60 Dye 2 2 B25 Ricinoloxazoline Niacac 8 60 Dye 2 2 B26 Ricinol oxazoline Cu-sol 8 60 Dye 2 2

5. Dyeing Tests with Basic Dye

5.1. Preparation of Dyeing Solution C

Astrazonrot 6B (dye “Dye 3”) was made into a paste by stirring with 60%acetic acid at 20° C. The two components were used in a quantity which,after subsequent addition to the aqueous matrix, produced aconcentration of 1.5% of each component, based on the aqueous matrix.

Beginning at 50° C., 100 g of sodium sulfate was first added, followedafter 5 minutes by the dye made into a paste with acetic acid. The wholewas then heated to boiling temperature at a rate of about 2° C. perminute. The dyeing solution thus prepared was used to test the dyecompatibility of polypropylene test specimens.

5.2. Dyeing and Evaluation

Untreated polypropylene test specimens and polypropylene test specimenssurface-modified in accordance with the invention were first stored for1 to 8 days at 20 to 60° C. and then immersed for 60 minutes in thedyeing solution prepared in accordance with 5.1, the boiling temperaturebeing maintained. The test specimens were then removed from the bath andrinsed with water first for 5 minutes at 50° C. and then for another 5minutes at 20° C. The dyeing results were visually evaluated by a panelof examiners using a “school marking system”. The individual values(“marks”) have the following meanings: 1=very good, 2=good,3=satisfactory, 4=adequate, 5=poor, 6=inadequate. The value “1”corresponds to the mark awarded in the corresponding dyeing of cottonwhile the value “6” corresponds to the mark awarded in the dyeing ofuntreated polypropylene.

The test results are set out in Table 3 below. All the results areaverage values from five tests.

TABLE 3 Dyeing tests with basic dye (dyeing solution C) Transition metalcompound Storage Result No. Additive (I) II Days ° C. Dye (mark) Comp.None None 1 20 Dye 3 6 Comp. None None 6 20 Dye 3 6 Comp. None None 1 60Dye 3 6 Comp. None None 6 60 Dye 3 6 B27 Soya oxazoline Pb-C8 3 20 Dye 33 B28 Soya oxazoline Pb-C8 8 60 Dye 3 2 B29 Soya oxazoline Niacac 3 20Dye 3 3 B30 Soya oxazoline Niacac 8 60 Dye 3 2 B31 Soya oxazoline Cu-sol3 20 Dye 3 3 B32 Soya oxazoline Cu-sol 8 60 Dye 3 2 B33 Ricinoloxazoline Pb-C8 8 60 Dye 3 2 B34 Ricinol oxazoline Niacac 8 60 Dye 3 2B35 Ricinol oxazoline Cu-sol 3 20 Dye 3 3 B36 Ricinol oxazoline Cu-sol 860 Dye 3 2 B37 Comperlan F Cu-sol 7 60 Dye 3 3 B38 Edenor HTiCT Cu-sol 220 Dye 3 3 B39 Edenor HTiCT Cu-sol 7 60 Dye 3 4 B40 Edenor HTiCT Pb-C8 220 Dye 3 3 B41 Edenor HTiCT Pb-C8 7 60 Dye 3 4

What is claimed is:
 1. A composition comprising: (a) a polyolefin; (b)from 0.01 to 10% by weight, based on the weight of the polyolefin, of amigratable amphiphile, excluding phenolic and sulfur-containingstabilizers and n-octyl phenyl salicylate; and (c) from 0.01 to 1000 ppmof a transition metal, based on the weight of the polyolefin.
 2. Thecomposition of claim 1 wherein the amphiphile has a molecular weight offrom 50 to 3000 daltons.
 3. The composition of claim 1 wherein theamphiphile has an iodine value of from 10 to
 200. 4. The composition ofclaim 1 wherein the amphiphile contains a substituent of high polarityselected from the group consisting of a carboxyl group, a hydroxylgroup, an amino group, an oxazoline group, an imidazoline group, anepoxide group, an isocyanate group, and derivatives thereof.
 5. Thecomposition of claim 1 wherein the transition metal is employed in theform of a transition metal salt.
 6. The composition of claim 1 whereinthe transition metal is present in the composition in an amount of lessthan 5 ppm, based on the weight of the polyolefin.
 7. The composition ofclaim 1 wherein the transition metal is selected from the groupconsisting of lead, nickel, zirconium, chromium, titanium, tin, andmixtures thereof.
 8. The composition of claim 1 wherein the polyolefinis selected from the group consisting of polyethylene, polypropylene,and mixtures thereof.
 9. The composition of claim 1 wherein theamphiphile and transition metal are present in the composition in aratio by weight of from 10:0.1 to 10:10⁻⁷.
 10. A process for making apolyolefin in composition having improved dye compatibility comprising:(a) providing a polyolefin; (b) providing from 0.01 to 10% by weight,based on the weight of the polyolefin, of a migratable amphiphile,excluding phenolic and sulfur-containing stabilizers and n-octyl phenylsalicylate; (c) providing from 0.01 to 1000 ppm of a transition metal,based on the weight of the polyolefin; and (d) combining (a)-(c) to formthe polyolefin composition.
 11. The process of claim 10 wherein theamphiphile has a molecular weight of from 50 to 3000 daltons.
 12. Theprocess of claim 10 wherein the amphiphile has an iodine value of from10 to
 200. 13. The process of claim 10 wherein the amphiphile contains asubstituent of high polarity selected from the group consisting of acarboxyl group, a hydroxyl group, an amino group, an oxazoline group, animidazoline group, an epoxide group, an isocyanate group, andderivatives thereof.
 14. The process of claim 10 wherein the transitionmetal is employed in the form of a transition metal salt.
 15. Theprocess of claim 10 wherein the transition metal is present in thecomposition in an amount of less than 5 ppm, based on the weight of thepolyolefin.
 16. The process of claim 10 wherein the transition metal isselected from the group consisting of lead, nickel, zirconium, chromium,titanium, tin, and mixtures thereof.
 17. The process of claim 10 whereinthe polyolefin is selected from the group consisting of polyethylene,polypropylene, and mixtures thereof.
 18. The process of claim 10 whereinthe amphiphile and transition metal are present in the composition in aratio by weight of from 10:0.1 to 10:10⁻⁷.
 19. The process of claim 10wherein (a)-(c) are combined by a method selected from the groupconsisting of extrusion, calendering, and injection molding, at atemperature of from 180 to 320° C.
 20. The process of claim 10 furthercomprising subsequently dyeing the polyolefin composition.